This invention relates to mounting implantable hearing aid transducers within the middle ear.
In an implantable hearing aid system, transducers within the middle ear engage an auditory element and transduce between electrical signals and mechanical vibrations. Middle ear hearing aid systems are not as susceptible to mechanical feedback as other types of systems. Such systems are more comfortable for the patient than other types of hearing aids, such as those placed directly in the external auditory canal. Transducers which contact an auditory element, such as one of the elements of the ossicular chain, require precise and reliable disposition within the middle ear. This is further complicated by anatomical variations among patients.
An implantable hearing aid (IHA) transducer support is mounted to the mastoid bone within a patient""s middle ear region. Input and output transducers are coupled to respective mounting portions on a single support. An electronics unit of the IHA is not attached to the support, simplifying implantation and attachment of the IHA support and transducers. When repairs or adjustments, such as replacing a battery, need to be made to the electronics unit of the IHA, it is not necessary to remove or adjust the support.
In one embodiment, a support comprises a single component. Input and output transducers are coupled""to respective mounting portions on opposite ends of the support prior to implantation. In a preferred embodiment, an arm extends from the support towards and into an access hole created behind the outer ear. The access hole is created, extending through the mastoid bone and into the patient""s ear. The arm is attached to the mastoid bone at its proximal end, providing more stability to the support. In an even more preferred embodiment, the arm extends outside the access hole, where it is mounted subcutaneously to the mastoid bone with a bone screw or other mechanical fastener. In a further embodiment, universal connectors are placed between the support and mounting portions for each transducer. The universal connectors, such as ball and socket joints, allow further adjustability and 360 degree movement to position the transducers against respective auditory elements.
In another embodiment, the position of the transducers within the middle ear cavity may be adjusted by manipulating a mechanical fastener that affixes the support to the mastoid bone. In this embodiment, the support comprises two components. Each of the components has an opening. At least one of the openings comprises an adjustment slot. The mechanical fastener extends through mutually-aligned slots/openings on alternate support components within the middle ear region. The distance between the transducers and the angle between the transducers and the support may be independently adjusted by positioning the adjustment slots with respect to the fastener. The resulting IHA support and transducers have positional stability and are invisible externally. In a further embodiment, universal connectors are placed between mounting portions for each transducer and each respective support component. The universal connectors, such as ball and socket joints, allow further adjustability and 360 degree movement to position the transducers against respective auditory elements.
In yet another embodiment, the position of the transducers within the middle ear region may be adjusted by manipulating two mechanical fasteners. In this embodiment, the support also comprises two components. Each component of the support has at least two adjustment slots or openings. Each of the two mechanical fasteners extends through mutually-aligned openings in opposite components. At least one of the two openings, through which a mechanical fastener extends, comprises a slot. The distance between the transducers is adjusted by positioning the adjustment slots/openings with respect to their respective fasteners. The resulting IHA support and transducers also have positional stability and are invisible externally.